Increase of the total efficiency using the Atkinson cycle in the spark ignition engine

The paper presents the results of investigations performed on a combustion engine with Atkinson cycle included and application of variable valve timing. Investigations were carried out at constant rotational speed 2500 and 3500 RPM and at throttle opening 25% and 50%. Influence of the advance/delay angle of inlet valves closing on formation of exhaust gases toxic components such as: carbon monoxide, hydrocarbons and nitric oxides was presented. Basing on the obtained results difference of toxicity of exhaust gases before and after application of phase shifter and their concentration in places of total efficiency increments was demonstrated. Especially The Atkinson cycle comparing with conventional Otto cycle, characteristics of the electric motor applied in Toyota Prius generation, starting and work of engines (combustion engine and electric motor) during vehicle standstill, relation of specific fuel consumption in function of rotational speed for a Toyota Prius engine, generation II, in total efficiency of engines with Atkinson cycle and Mitsubishi GDI in function of rotational speed, relative increase in total efficiency as rotational speed function, influence of intake valves opening angle on concentration in exhaust gases: carbon monoxide, hydrocarbons and nitric oxides at diferrent throttle opening values are presented in the paper.